Significance of Metastable Acceptors in Cu(In,Ga)Se2 Solar Cells in Accelerated Lifetime Testing

Harvey Guthrey, Jiro Nishinaga, Yukiko Kamikawa, Shogo Ishizuka, Hajime Shibata, Shigeru Niki

Research output: Contribution to journalArticlepeer-review

7 Scopus Citations


The significance of metastable acceptors in Cu(In,Ga)Se2 (CIGS) solar cells in accelerated lifetime testing has been investigated. Dry heating under light irradiation improves the conversion efficiency of CIGS solar cells at the early stage, which slightly decreases after long-term testing. However, after dry heating in the dark, the conversion efficiency significantly decreases. The net acceptor concentration considerably decreases after dark heating, and the reduction in the number of metastable acceptors results in decreases in open-circuit voltage and fill factor. After heat illumination treatment, the net acceptor concentration increases because of the metastable acceptors in CIGS layers, and the open-circuit voltage and fill factor partly recover. Therefore, the concentrations of metastable acceptors should be controlled by light irradiation or current injection with positive bias to evaluate correctly the degradation rates during accelerated lifetime testing.

Original languageAmerican English
Article number092301
Number of pages6
JournalJapanese Journal of Applied Physics, Part 2: Letters
Issue number9
StatePublished - 2018

Bibliographical note

Publisher Copyright:
© 2018 The Japan Society of Applied Physics.

NREL Publication Number

  • NREL/JA-5K00-72514


  • conversion efficiency
  • degradation
  • efficiency
  • irradiation
  • open circuit voltage


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